Oil circuit breaker



Aug. 28, 1951 G SCARPA 2,566,095

OIL CIRCUIT BREAKER Filed Jan. 22, 1947 3 Sheets-Sheet l l F/G. 3.

7 I Q W 5 7/ 4 I] 72 fi/az E I INVENTQR. E BY E w I? I) Aug. 28, 1951 S R I 2,566,095

OIL CIRCUIT BREAKER Filed Jan. 22, 1947 3 Sheet-sSheet 2 O @J I I I a? I Piaf I; I 1 I 6/ m; Mn; M 45 I as a 63 h: Q m

I? N s o 70 E1 a M V K/ K Aug. 28, 1951 SCARPA 2,566,095

OIL CIRCUIT BREAKER Filed Jan. 22, 1947 3 SheetsSheet 5 0 II |ll O I O O I I Z I '0' [1 Z/ O HI 0 4,

j INVENTOR.

BY W S- 2 Off" Patented Aug. 28, 1951 OIL CIRCUIT BREAKER Giuseppe Scarpa, Milano, Italy Application January 22, 1947, Serial No. 723,607 In Italy January 21, 1946 Section 1, Public Law 690, August 8, 1946 Patent expires January 21, 1966 6 Claims. 1

The present invention relates to an oil circuit breaker of the column type wherein, by the use of an improved type of explosion chamber, and of an improved actuating system, a highly effective performance is obtained.

The circuit breaker according to the invention is characterized by a labyrinth chamber having a plurality of small cavities filled with oil and arranged at different levels, and dilferent radial directions in the arc is trapped so as to bring about many radially directed blasts of oil vapors, each extending in only one direction.

According to another embodiment, the circuit operation of the breaker may be mechanically obtained in a very simple way by means of a shaft, levers and appropriate connecting elements.

Further, according to the present invention a movable hollow contact plunger is provided, so that during its downward motion Within the lower part of the enclosing tank, which preferably is separated from the upper one through a diaphragm, a jet of oil is produced at the head of said plunger and directed into the explosion chamber, so that it cooperates effectively in extinguishing the are.

A transformer within the oil filled lower part of the same circuit breaker is also provided, as well as an insulating cylindrical casing protecting all metallic parts under tension.

According to a modified embodiment of the present invention a pantograph device is arranged between the contact plunger and the insulating actuating rod for reducing the stroke and the speed of the operating rod in respect to those of the contact plunger.

Other features will be fully described in the following description which will be best understood together with the accompanying drawings in which:

Fig. l is a partial sectional side elevation of a pole of a breaker, according to the present invenion;

Figs. 2 and 2a are two cross-sectional views along an axial and a radial plane respectively of the embodiment shown in Fig. 1;

Fig. 3 is a sectional view of a detail of the operating cylinder and of the locking and signaling device;

Fig. 4 is an axial section of another embodiment of the improved breaker according to the invention;

Fig. 5 is a cross-section of another embodiment of the invention, in which the explosion chamber is located at the bottom instead of at the top of the column and a Fig. 6 is an axial section of the central part of an embodiment provided with a pantograph device.

In the embodiment illustrated by Figs. 1, 2 and 3, the reference numeral l indicates the terminals, 2 the stationary contact, 3 the movable contact, 4 the piston which operates the lifting of said contact, 5 the cylinder into which slides said piston, 6 the stop ring of the movable contact, I a latch locking the movable contact 3 in its closed position; 8 the spring which brings about the opening of the breaker whenever latch 1 is disengaged; 9, l0, H, l2 are the intermediate members for transmitting the movement between latch I and the insulating rod l3, which is actuated in order to open the switch of the operating solenoid l4; I5 indicates an insulating tube concentric with rod iii, in which flows the compressed air coming from the reservoir l6, whenever magnet I1 is actuated; l8 indicates a manually operated auxiliary pump for producing pressure in the reservoir before the closing of the breaker in the event that the supply of air from another source should fail: 19 indicates the insulating supportin body of the circuit breaker in which a transformer may be arranged; 20 indicates the insulating body of the breaker proper, 2| the labyrinth chamber having a central hole 25 (Fig. 2) almost equal to the diameter of movable contact 3; 22 is the lower chamber defined by a cylindrical extension or sleeve 23; 24 is a nozzle situated above the explosion chamber 21 and having a diameter much larger than that of the movable contact 3.

Fig. 2 shows, at an enlarged scale, chamber or member 2|; in it, reference numeral 25 indicates the holes forming a central boring having a diameter almost equal to that of movable contact 3, 26 are cavities of much larger diameter, coaxial with holes 25; 21 are cavities axially arranged in respect to holes 25 so as to extend tangentially to same, and located one over the other.

Fig. 3 shows the members operating and looking the movable contact. The lower part of the movable contact plunger 3 actuates piston ,4, which slides into cylinder 5, and carries a stop ring 6 with which engages latch 1, which holds loaded the compressed opening spring 8. 9 indicates the slidable rod which, actuated by link l0 and lever II, can force wedge 28 against stud 29 and actuate latch 1 disengaging ring 6, thereby releasing spring 8, so as to rapidly push downward contact stem 3; 30 indicates the compressed air input conduit to cylinder 5 which, operating on piston 4, lifts the contact stem and causes .ring 6 to engage with latch l, which locks the contact stem in the closed position; 3| indicates a small two armed lever which, when ring 6 is in the latched position, by means of link 32 holds down slidable rod 33, which operates the signal members of the circuit breaker; when contact stem fitmoves downwards spningid-isallowed :to lift upwards slidable rod 33--andto modify the position of the signal members.

The operation of the circuit breaker described above is the following: To close the breaker it is necessary to build up a pressure in *reservoir'ifi by means of pump [8, or by connectingit-to. a compressed air distributing system; thereafter magnet valve i1 is actuated -by h-and or electr'ically, thereby admitting compressed-airto cylplunger 3 to engage with stationary contact!!- and at the same time, by compressing spring 8,

4 the preceding one, that is the circuit breaker has again an outer insulating sleeve 5|, stationary contact 52, a movable plunger 53 with an axial hole, and a dividing partition between upper and lower part of the breaker. Differently how- :ever'from the preceding embodiment, plunger 53 is .not directlyconnected to the operating links and levers, but at a certain intermediate point :same is replaced by a pantograph system 59 apt to multiply the stroke and speed of the upper end of plunger 53, in relation to the part connectedqto. the operating levers.

The'advantages offered by such an arrangementin additionlto those already considered inder 5, which acting on piston4,.liftsmovable above are evident.

..The circuit breaker illustrated in Fig. 5 differs only little irom those considered before inascauses ring 6 to engage with latch I, thereby-lock ing the contacts in their closed position.

' F'Bo'openttheicircuit zbreakerrrod ,l.3;is actuated :by .meansofzwmagnet valve 1:4 or-by jhand, thus acting through members [2, II, In and 9 on latch 1 fl :and thereby freleasing r spring 8 which causes nd-ropping .of contact .stem .3. {Thus an arc :is started :be'tween Tithe upper end of --said stem and stationary contact :2; .gsaid :arc is trapped :in the labryinth chamber i 21 where, on account .of oil .vaporisatiomit' is subjected to radially directed lgas blasts :on different levels, :and in different radial directions-xandithis' facilitates the breakin of thecentral nondeionized path .of the, arc zone when :the .currentlpasses through zero, :prevent- 'f-ing the restablishing of :thetarc.

If, the current having reached a..critical value;

the extinction: of "the :arc does inot take place inside the labyrinth chamber, :the; expanding fare .vaporizes the-' oilmcontained in .chamber 22; the agases contained therein may 'escape' only in .a very jlimited quantity through ;'the.;.axial hole of the iabyr'inthuchamber, due ito :the high resistance cthey meet :by the reduced section :of said hole 25 and to theleffect .of the radially moving gas blasts, and force the oilzto rise -through the space -externa1 :to'the labyrinth :chamber, and to esicape through hole 24Where-said oil, directed across :the path vof t'he arc'causes its extinction at the next :passagev of the current through; zero.

According to the embodiment-shown in 1 Fig.

'4; the circuit breaker comprises acylindrical outer =s1eeve 4| of insulating material insulatingthe fdifferent'live parts: and constituting at the same time their-lain body of the breaker.

'Said body 41 carries the stationary contact 42 in whose cavity-the upper end of themovable plunger 43 is "engaged passing through the laby- "rinthc'hamber 44. Plunger 43*, however, hasan -axial ho'le: 43', through. which flows an oil stream into the 'explosion c-hamber 44, when plunger 43 -is -dropped, the loweroil'containing chamber be The embodiment .shown I in Fig. 6 :isvsimilar :to'

and J m-and controlled by shaft 66.

much as in it the stationary contact 62 is placed atuthe lower end instead of at the upper end, and above same the labyrinth explosion chamber ;is arranged throughwhichmovableplunger 63, passes guided and actuated by levers-61, -68,69 On the disks .co-nstituting the labyrinth chamber 64 areprothiscircuit breakeris similarto those previously considered and .has th-erefore the samenadvantages in addition to having -a -betterlg.uided operating rod.

-What Lolaimis;

.1. Ina circuit breaker-with a rod-shaped movable contact, q-anv oileimmersed arc extinguishing member comprising in combination, an'elongated .centralboring'having substantiallythe same di- --ameter..as-.the contacttextending through said boring .in the .closed-position of the breaker; a first cavity in the member, said first cavityextending in a-first radial direction from said central boring and communicating therewith; and asecond cavityainthe member, said second cavity .being arranged at a difierentlevel with respect tosaidboring from the level of said firstcavity and extending in a secondradial direction dif- .ferent:fro=m the .first radial-direction fromsai-d central boring and communicating therewith, whereby said cavities form together with said central boring a labyrinth passage for the are which is subdivided into separate portions by said cavities. V 2. In a circuit breaker with a rod-sha-pedmovable contact, an oil-immersed arc extinguishing membercomprising in combination,- an elongated central boring having substantially the same diameter as the contact extending through said boring in thecl-osed-position of the breakerya first cavity in the member, said first cavity extending inafirst radial directionfrom said central boring and communicating therewith; :a second cavity in the member, said second cavity being arranged at a different level with respect to said boringzfrom the level'of said firstcavity and :extending in asecond radial direction'different from the first radial direction :from said central boring and communicating therewith; and a third cavity in the member, said third cavity being arranged at a different level with respect to said boring from the levels of said first and second cavities and extending in a third radial direction difierent from the first and second radial directions from said central borin and communicating therewith.

3. In a circuit breaker with a rod-shaped movable contact, an oil-immersed are extinguishing member comprising in combination, an elongated central boring having substantially the same diameter as the contact extending through said boring in the closed position of the breaker; a plurality of substantially circular cavities communicating with the boring and arranged in the member eccentrically with respect to'said boring at difierent levels and in diirerent radial directions, respectively; and a substantially circular cavity having a larger diameter than each of said eccentrically arranged circular cavities and being centered with respect to said boring and communicating therewith, whereby said cavities form together with said central boring a labyrinth passage for the are which is subdivided into separate portions by said cavities.

4. In a circuit breaker with a rod-shaped movable contact, an oil-immersed arc extinguishing member comprising in combination, an elongated central boring having substantially the same di ameter as the contact extending through said boring in the closed position of the breaker; a plurality of substantially circular cavities communicating with the boring and arranged in the member eccentrically with respect to said boring at difierent levels and in different radial directions, respectively; and two substantially circular cavities having a larger diameter than each of said eccentrically arranged circular cavities and being centered with respect to said boring and communicating therewith, said centered cavities being arranged, respectively, below the level of the lowest and above the level of the highest of said eccentrically arranged circular cavities, whereby said cavities form together with said central boring a labyrinth passage for the are which is subdivided into separate portions by said cavities.

5. In a circuit breaker with a rod-shaped movable contact, an oil-immersed arc extinguishing member comprising in combination, an elongated central boring having substantially the same diameter as the contact extending through said boring in the closed position of the breaker; a plurality of substantially circular cavities communicating with the boring and arranged in the member eccentrically with respect to said boring at different levels and in different radial directions, respectively; a substantially circular cavity having a larger diameter than each of said eccentrically arranged circular cavities and being centered with respect to said boring and communicating therewith, whereby said cavities form together with said central boring a labyrinth passage for the are which is subdivided into separate portions by said cavities; and a cylindrical extension forming part of the member and being arranged at the end of said boring near said centered cavity.

6. In a circuit breaker with a rod-shaped movable contact, an oil-immersed arc extinguishing member comprising in combination, an elongated central boring having substantially the same diameter as the contact extending through said boring in the closed position of the breaker; a plurality of substantially circular cavities communicating with the boring and arranged in the member eccentrically with respect to said boring at dififerent levels and in different radial dir-ec tions, respectively; two substantially circular cavities having a larger diameter than each of said eccentrically arranged circular cavities and being centered with respect to said boring and communicating therewith, said centered cavities being arranged, respectively, below the level of the lowest and above the level of the highest of said eccentrically arranged circular cavities; and a cylindrical extension forming part of the member and being arranged at the end of said boring near said centered cavity arranged below the level of the lowest of said eccentrically arranged circular cavities, whereby said cavities form together with said central boring a labyrinth passage for the are which is subdivided into separate portions by said cavities.

GIUSEPPE SCARPA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,067,735 Hewlett July 15, 1913 1,899,612 Dyer Feb. 28, 1933 1,934,454 Spurgeon Nov. 7, 1933 1,981,709 Rawlins Nov. 20, 1934 1,988,120 Hillebrand Jan. 15, 1935 2,022,241 Kopeliowitsch Nov. 26, 1935 2,106,032 Lange Jan. 18, 1938 2,109,685 Ainsworth Mar. 1, 1938 2,145,706 Brann Jan. 31, 1939 2,315,618 Huttstutter Apr. 6, 1943 2,342,809 Ludwig et a1 Feb. 29, 1944 

